DIY Network

Gilded Three-Panel Screen: Copper-Guilding and Patina Technique From "Wood Works" episode WWK-610

	The copper-gilded panels feature a textured patina finish.
	Much like the veins of color in marble, the rich, red color of the red Japan-paint shines through the cracks and gaps in the patinaed copper leaf.

Host David Marks builds an elegant three-panel screen. With the frame built, and the panels painted with red Japan-paint, the painted panels can now be gilded with copper leaf, then given a patina using oxidizing chemicals

Materials:

Copper leaf (or other gilding leaf)
Gold size (adhesive)
Gilding tools (brushes, etc.)
Goat-hair brush
Cheesecloth
Wax paper
Paper towels
Plastic-covered board
Potash sulfurated
Sodium sulfide
Mixing containers; stir sticks
Spray bottle
Safety glasses or goggles
Protective gloves

Safety Alert: Always wear protective gloves, and ensure adequate ventilation, when working with wood stains, solvents and other toxic solutions. When working with some sprays and chemicals, a respirator mask may be required.

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Copper-Leaf Gilding

Gilding with copper achieves a finish that could never be achieved with just paint. Gilding adds a new dimension to your work -- a distinctive luster that adds both depth and texture.

• Size -- or adhesive -- is applied to the panel (figure A) prior to application of the copper leaf. Size is like varnish in that it's oil-based and dries quickly.

  Important: When applying size, work in a well ventilated area. Also make sure that, once the size is applied to the surface, no dust is created in the workshop that could adhere to the size.

• It takes about an hour for the size to set up, or tack -- i.e., reaching the right sticky consistency for applying the copper leaf.

  Tip: You can check the size by placing your knuckle on the surface (figure B). If the surface feels like it has about the same level of "stickiness" as masking tape, it's ready for application of the leaf.

  Figure A

  Figure B

  
  

  
  

• Copper leaf comes in a book containing individual and extremely fine sheets of copper that have been rolled into a thickness much thinner than paper (figure C). The sheets are typically 5-1/2" square.

• To apply, simply press the copper-leaf sheet onto the sticky surface of the panel (figure D). As soon as the leaf is pressed against the size, it detaches from its paper backing.

  Figure C

  Figure D

  
  

  
  

• The method that we used to apply the leaf is termed notan gilding -- a Japanese term that refers to creating negative space. The cracks and tears created in the leaf will allow the paint to show through. As you apply the entire surface (figure E), consider the balance between the copper and the red paint.

• Tip: If you're new to gilding, it may be advisable to size one half of a panel at a time since the window of time for the size to set up is small.

• Once the panel is gilded, burnish surface by applying pressure with some wax paper (figure F).

  Figure E

  Figure F

  
  

• Once the surface has been gilded, allow the panel to set for 12 hours. Then use a goat-hair brush to brush away excess pieces of the leaf (figure G). The process of removing the excess is called tamping, and the leftover pieces of leaf are termed skewings. Carefully brush away the skewings. You may want to save the skewings in a jar for future projects.

• Once all of the panels have been gilded on one side in copper (figure H), they're ready to be given a patina finish to bring out a variety of colors in the copper and give the surface a rich texture.

  Tip: It's best to apply the chemical patina after gilding only one side of the three panels. After the patina on those sides is complete, and has been sealed with a vinyl sealer, you can turn the panels over and repeat the process on the other sides. In that way, the chemicals won't drip over to the opposing sides and spoil the finish.

  Figure G

  Figure H

  
  

Safety Alert: The chemicals used in this procedure are toxic. Be certain to exercise proper safety precautions, and wear protective gloves and safety goggles.

• To create the patina, mix 1/4 tsp. of potash sulfurated into 1/2 cup of warm water (figure I).

• Then mix 1/2 tsp. of sodium sulfide with 1/2 cup of warm water (figure J) and stir.

  Figure I

  Figure J

  
  

• Carefully pour the individual solutions into separate larger containers.

• Place all three panels side-by-side with the gilded side facing up.

• To create texture, use some tissue paper sprayed with water. Spray the tissue with water and lay it across the gilded surface, leaving some folds and air pockets beneath the tissues.
  

• Now take a sponge, soaked in the sodium sulfide solution, and apply it to the tissue (figure K). The reaction will occur immediately. The chemicals will travel through the tissue by capillary attraction, and will begin darkening areas the surface by oxidizing the the metal.

• Once you're happy with the resulting pattern (figure L), spray on water to stop the reaction, then blot the surface with paper towels to remove any excess. Allow the surface to dry.

  Figure K

  Figure L

  
  

• Now you can begin the treatment that will create a dramatic pattern across all three panels. Soak a wide strip of cheesecloth in the potash-sulfurated solution. Stretch out the cheesecloth onto a long, plastic-covered board (figure M).

• Flip the board and cheesecloth onto the upper portion of all three panels (figure N).

  Figure M

  Figure N

  
  

  Figure O

• Lift the board, leaving the plastic and cheesecloth across the panels. Then gently press down on the plastic to set the cheesecloth. As the chemical reacts with the copper, the copper surface tarnishes -- leaving the surface textured by the pattern of the cheesecloth (figure O).

• Leave the panels to dry in the sun. As it dries, the sun will stop the chemical reaction.

Tip: If you're left with any areas remaining that are too shiny, you can use a spray-bottle filled with the sodium-sulfide solution to soften the highlights.

In the segment that follows, the three-panel screen is assembled and given a final finish.

RESOURCES :

Woodworking Techniques: Best Methods for Building Furniture from Fine Woodworking
Author: Editors of Fine Woodworking magazine
Publisher: Taunton Press
ISBN: 1561583456

David Marks Website
David Marks, DIY's Wood Works host, is a master woodworker. For more information on cut sizes and project details, please contact him via his Website at www.djmarks.com

Woodworker's Guide to Wood: Softwoods, Hardwoods, Plywoods, Composite, Veneers
Model: 080836878
Author: Rick Peters
(2000)
Sterling Publishing Co. Inc.
Website: www.sterlingpub.com

Fine Woodworking
A magazine devoted to high-quality craftsmanship in woodworking.
The Taunton Press Inc.
Website: www.taunton.com